I would wait one more generation until upgrading. You aren't going to see enough difference between the 930 and a 2500k at say 4 GHz to warrant the cost.
Based on the width (200mm) of your case, a 212 EVO would have no problem fitting in that case.
I could be way off, but used PC components don't go for much unless they're hard to find and in great demand. For that reason, I think the max to ask for is $150 (USD)